Red blood cell adhesiveness/aggregation, C-reactive protein, fibrinogen, and erythrocyte sedimentation rate in healthy adults and in those with atherosclerotic risk factors

Obstructive sleep apnea (OSA) is associated with an increased incidence of stroke and myocardial infarction as well as increased prothrombotic and inflammatory processes. Although erythrocyte adhesiveness/aggregation is known to be elevated in cardiovascular diseases, it has never been evaluated in OSA. The aim of this study was to examine the possible association of OSA and erythrocyte adhesiveness/aggregation.

The study was conducted in the Sleep Laboratory of a tertiary university-affiliated medical center in 79 patients (age 57.1 ± 12.9 years) with a diagnosis of OSA (apnea hypopnea index 41.2 ± 25.9). Findings were compared with data on 1079 controls without clinical symptoms of OSA, matched for sex, age, and body mass index. Overnight polysomnography and blood sampling for erythrocyte sedimentation rate, levels of fibrinogen, high-sensitivity C-reactive protein, and erythrocyte adhesion/aggregation test consisting of measures of erythrocyte percentage and vacuum range on image analysis.

The study group had significantly higher values than controls of all three markers of inflammation (p < 0.001 for erythrocyte sedimentation rate and fibrinogen; p = 0.037 for C-reactive protein). Erythrocyte percentage was significantly lower in the sleep apnea group (84.05 ± 15.97 vs. 90.79 ± 11.23%, p < 0.001), and vacuum range was significantly higher (8.22 ± 7.98 vs. 4.63 ± 4.05 μm, p < 0.001), indicating stronger erythrocyte adhesion/aggregation. Both these factors were significantly correlated with erythrocyte sedimentation rate and to hs-CRP (percentage: r = − 0.630; 0.258, p = 0.005; 0.031; vacuum range: r = 0.494; − 0.328, p = 0.001; 0.005 respectively).

OSA is associated with increased erythrocyte aggregation/adhesion, which is correlated with an increase in inflammation markers. These findings might help explain the increased cardiovascular morbidity in OSA.

To asses the degree of erythrocyte aggregation in the peripheral blood of women with preterm premature rupture of the membranes (PPROM).

This was a prospective case control study. Twenty patients with preterm premature rupture of the membranes and matched controls were recruited at the Lis Maternity Hospital. A slide test and image analysis were used to quantitate the degree of erythrocyte aggregation. Hematological indices and markers of inflammation such as the erythrocyte sedimentation rate and C-reactive protein were also compared.

The vacuum radius (VR) of the study group was significantly higher than in the control group at 14.8 ± 1.6 μm versus 10.0 ± 1.0 μm, respectively (P = 0.03). Other hematological indices were not changed significantly between the groups.

We found an increase in erythrocyte aggregation in the peripheral blood of patients with preterm premature rupture of the membranes. We used this sensitive marker of inflammation to further support the theory that PPROM is an inflammatory state.

Hypertension and estrogens are both prothrombotic. We used the microchannel method to investigate whether hormone replacement therapy (HRT) with conjugated equine estrogen (CEE) plus medroxyprogesterone acetate (MPA) affects blood flow through the microchannels in hypertensive postmenopausal women being treated with antihypertensive drugs and in normotensive postmenopausal women.

Sixty-two consecutive postmenopausal women were randomly assigned to a hypertensive HRT group (n = 16), hypertensive control group (n = 15), normotensive HRT group (n = 16) and normotensive control group (n = 15). Each HRT group received CEE 0.625 mg plus MPA 2.5 mg daily orally for 12 months. Both hypertensive groups were being treated with antihypertensive drugs before the study. Microvascular blood flow was assessed on the basis of blood passage time, the time required for 100 μl of whole blood to pass through a cylinder, was determined before and 12 months after the start of HRT by the microchannel method (micro channel array flow analyzer).

CEE plus MPA therapy did not change blood passage time in any of the groups. Microscopic observation showed that the whole blood passed smoothly through the microchannels in every group.

CEE plus MPA therapy may not impair blood flow through the microchannels in hypertensive postmenopausal women receiving antihypertensive drugs or in normotensive postmenopausal women. However, administration of CEE plus MPA to postmenopausal women with hypertension warrants caution against the occurrence of thromboembolic events.